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  <script>
    function curry(fn) {
      const len = fn.length
      return function curried(...args) {        
        if(args.length >= len) {
          return fn(...args)
        }else{
          // return curried.bind(this, ...args)
          return function (...last) {
            return curried(...args, ...last)
          }
        }
      }
    }
    const sum = (a, b, c)=> {
      return a + b + c
    }
    const curried = curry(sum)
    console.log(curried(1)(2))
    console.log(curried(1)(2)(3))
  </script>
</body>
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